SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03de71580fdb9b3096b41ecbee9c86bfd71839bc641b17d54dbd2b898a6fa13f' 
  AND token = 'WauTF8HYbZhwnpu1YrAMocw+jotDWCrAiY5coT4viMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}